feat(fuse-driver): implement dwarfs.inodeinfo xattr

include/dwarfs/filesystem_v2.h

@@ -174,6 +174,10 @@ class filesystem_v2 {
 
   history const& get_history() const { return impl_->get_history(); }
 
+  folly::dynamic get_inode_info(inode_view entry) const {
+    return impl_->get_inode_info(entry);
+  }
+
   class impl {
    public:
     virtual ~impl() = default;
@@ -214,6 +218,7 @@ class filesystem_v2 {
     virtual size_t num_blocks() const = 0;
     virtual bool has_symlinks() const = 0;
     virtual history const& get_history() const = 0;
+    virtual folly::dynamic get_inode_info(inode_view entry) const = 0;
   };
 
  private:

include/dwarfs/metadata_v2.h

@@ -134,6 +134,10 @@ class metadata_v2 {
 
   bool has_symlinks() const { return impl_->has_symlinks(); }
 
+  folly::dynamic get_inode_info(inode_view iv) const {
+    return impl_->get_inode_info(iv);
+  }
+
   static std::pair<std::vector<uint8_t>, std::vector<uint8_t>>
   freeze(const thrift::metadata::metadata& data);
 
@@ -188,6 +192,8 @@ class metadata_v2 {
     virtual size_t block_size() const = 0;
 
     virtual bool has_symlinks() const = 0;
+
+    virtual folly::dynamic get_inode_info(inode_view iv) const = 0;
   };
 
  private:

src/dwarfs/filesystem_v2.cpp

@@ -387,6 +387,9 @@ class filesystem_ final : public filesystem_v2::impl {
   size_t num_blocks() const override { return ir_.num_blocks(); }
   bool has_symlinks() const override { return meta_.has_symlinks(); }
   history const& get_history() const override { return history_; }
+  folly::dynamic get_inode_info(inode_view entry) const override {
+    return meta_.get_inode_info(entry);
+  }
 
  private:
   filesystem_info const& get_info() const;

src/dwarfs/metadata_v2.cpp

@@ -447,6 +447,8 @@ class metadata_ final : public metadata_v2::impl {
 
   bool has_symlinks() const override { return !meta_.symlink_table().empty(); }
 
+  folly::dynamic get_inode_info(inode_view iv) const override;
+
  private:
   template <typename K>
   using set_type = folly::F14ValueSet<K>;
@@ -1525,6 +1527,40 @@ metadata_<LoggerPolicy>::get_chunks(int inode) const {
   return get_chunk_range(inode - inode_offset_);
 }
 
+template <typename LoggerPolicy>
+folly::dynamic metadata_<LoggerPolicy>::get_inode_info(inode_view iv) const {
+  folly::dynamic obj = folly::dynamic::object;
+
+  auto chunk_range = get_chunk_range(iv.inode_num());
+
+  if (chunk_range) {
+    obj["chunks"] = folly::dynamic::array;
+
+    for (auto const& chunk : *chunk_range) {
+      folly::dynamic chk = folly::dynamic::object;
+
+      chk["block"] = chunk.block();
+      chk["offset"] = chunk.offset();
+      chk["size"] = chunk.size();
+
+      if (meta_.category_names() && meta_.block_categories()) {
+        chk["category"] =
+            meta_.category_names()
+                .value()[meta_.block_categories().value()[chunk.block()]];
+      }
+
+      obj["chunks"].push_back(chk);
+    }
+  }
+
+  obj["mode"] = iv.mode();
+  obj["modestring"] = modestring(iv.mode());
+  obj["uid"] = iv.getuid();
+  obj["gid"] = iv.getgid();
+
+  return obj;
+}
+
 std::pair<std::vector<uint8_t>, std::vector<uint8_t>>
 metadata_v2::freeze(const thrift::metadata::metadata& data) {
   return freeze_to_buffer(data);

src/dwarfs_main.cpp

@@ -36,6 +36,7 @@
 #include <folly/Conv.h>
 #include <folly/String.h>
 #include <folly/experimental/symbolizer/SignalHandler.h>
+#include <folly/json.h>
 
 #ifndef DWARFS_FUSE_LOWLEVEL
 #define DWARFS_FUSE_LOWLEVEL 1
@@ -182,6 +183,7 @@ namespace {
 
 constexpr std::string_view pid_xattr{"user.dwarfs.driver.pid"};
 constexpr std::string_view perfmon_xattr{"user.dwarfs.driver.perfmon"};
+constexpr std::string_view inodeinfo_xattr{"user.dwarfs.inodeinfo"};
 
 } // namespace
 
@@ -828,6 +830,17 @@ void op_getxattr(fuse_req_t req, fuse_ino_t ino, char const* name,
         oss << "no performance monitor support\n";
 #endif
       }
+    } else {
+      if (name == inodeinfo_xattr) {
+        auto entry = userdata->fs.find(ino);
+
+        if (entry) {
+          auto ii = userdata->fs.get_inode_info(*entry);
+          oss << folly::toPrettyJson(ii) << "\n";
+        } else {
+          err = ENOENT;
+        }
+      }
     }
 
     auto value = oss.view();
@@ -886,6 +899,8 @@ void op_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size) {
     if (ino == FUSE_ROOT_ID) {
       oss << pid_xattr << '\0';
       oss << perfmon_xattr << '\0';
+    } else {
+      oss << inodeinfo_xattr << '\0';
     }
 
     auto xattrs = oss.view();